Our studies of the natural history of renal disease in patients with GSD-1 has led us to suggest that the renal lesion in GSD-1 may be an example of hemodynamically (glomerular hyperfiltration/hypertension) mediated disease. The mechanism underlying hyperfiltration is being explored. In addition a therapeutic trial has been initiated using captopril, in angiotensin converting enzyme inhibitor, since this agent has been effective in animal models of glomerular hyperfiltration.